Production of metal castings



Feb. 6, 1934. w BAILEY 1,946,450

P RODUCTION OF METAL CASTINGS Filed July 18, 1931 2 Sheets$heet 1 IINVENTOR Richard I. ailey ATTORNEY Fe 5, 1934. R. w. BAILEY 6,

PRODUCTION OF METAL CASTINGS Filed July 18, 1931 2 Sheets-Sheet 2IuvEN'rdR Richard W. Bailey BY ATTORNEY Patented Feb. 6, 1934 UNITED"STATES PATENT OFFICE PRODUCTION OF METAL CASTINGS Richard WilliamBailey, Hale, England, assignor to Associated Electrical IndustriesLimited, a company of Great Britain Application July 18, 1931, SerialNo. 551,769, and

in Great Britain August 15, 1930 7 Claims. '(Cl. 22-200) This inventionrelates to the production of ingots, that complete solidification of thelower metal castings and particularly, though not expart of an ingotshall take place well inadvance clusively, to the production of ingotsof cast of the solidification of the upper part and that steel.solidification shall proceed in the upward direc- In the production ofcast steel ingots, particution, asthis is found to result in fewerdefects in 60 larly of large size, variations in grain structure theaxial region of the ingot. This can readily usually occurinvarious partsof the ingot. These be accomplished according to my invention by mayresult in segregation and cracks in the outer permitting the molten leadto remain in the lower parts of ingots of all shapes and of what arepart of the mould for a suitable time and by then 10 called ingot comermarks in the case of ingots raising its level either by stages orcontinuously. 06 of square and polygonal cross section. Defects The rateof cooling may be varied at various parts also generally found in theaxial region of an inof the ingot by raising and lowering the level ofgot, particularly in the upper part. the lead in the mould. Variation ofthe rate and The objectof the present invention is to reducedistribution of cooling of the ingot by the means the liability for theformation of such defects and described may be combined with heating orcool- 70 generally to produce an ingot of improved sounding of the mouldwhereby the rate and distribuness and quality. tion of the cooling ofthe ingot may be more closely According to my invention I provide forthe incontrolled. For example, in order to cool the troduction, at adesired stage in the casting procmould, air may be blown over a part ofthe exess or even after pouring is completed, of a suitternal surface ofthe mould which may, for greater 76 able low melting point metal oralloy into the efiect, be formed with ribs; or the mould wall spaceformed between the mould and the castmay otherwise be made to present anextended ing by the contraction of the latter and/or the surface forthe'extraction of heat. Similarly, in expansion of the mould. Means arealso advanplace of cooling air, gaseous or other heating metageouslyprovided whereby the height of the free dium may be employed, and whenit may be neces- 80 surface of the liquid filling metal thus introducedsary, at a particular stage of the cooling, to acmay be varied asdesired. By this means the centuate the relative rates of solidificationat hydrostatic, pressure of the still molten metal different parts of aningot, cooling of one part of within the outer shell of the castingwhere solidia mould maybe eflected in conjunction with heatficationfirst occurs can be counteracted at any ing of another part. The .moltenfilling metal 86 desired stage by the hydrostatic pressure of the maybeintroduced into the mould at a certain liquid metal introduced betweenthe shell and the point in the casting process, in some cases aftermould, and, furthermore, the presence of metal the pouring is completed,for the purpose only of between the casting and the mould will increasecontrolling the rate of cooling, or the liquid metal the rate of coolingof the casting so that, by varymay be introduced solely for the purposeof pro- 90 ing the height of the metal introduced, the rate viding acounteracting hydrostatic pressure on and manner of cooling of thecasting can be conthe outside of the casting. trolled by varying thelevel of the liquid metal. To provide for the introduction andwithdrawal When it is desired to remove the casting from the of theliquid filling metal, an opening or port of mould the metal introducedmay be run out besuitable size may be formed in the side of the 9 fore.lifting the castingmould near or at the bottom or even in the bot- Incarrying out the invention in casting, for tom itself; and, ifnecessary, means such as chanexample, a large steel ingot, as soon as acertain nels are provided fordistributing the filling-metal amount ofsteel has been poured, molten metal, to the sides of the mould. In onearrangement,

lead for example, is admitted near the bottom of for example, saidopening is provided with a plug 100 the mould, preferably through anopeningjn the with means for screwing same in and out so as to side ofthe mould, at a rate which maintains. the open and close the port forthe admission and level of the lead at an appropriate distance belowwithdrawal of the liquid filling metal as required the free surface ofthe steel as pouring is conand to prevent access of the moltenmetal tobe tinued. When it is judged that the thickness of cast to the conduitsor passages by which the 105 the shell of the ingot is such as towithstand the filling metal is introduced. Theouterside of thehydrostatic pressure of the still liquid steel in the port communicatesthrough a conduit with 8. interior of the ingot the level of the leadmay be reservoir for the liquid filling metal. The level of lowered soas to reduce the rate of cooling of the metal in the mould can beregulated by varying ingot. It is usually desired, in thecase of steelthe height of molten metal in the reservoir or 10 the reservoir may bein the form of a cylinder containing 21. weight or a loosely fittedpiston, the pressure of which can be varied, pressing on the uppersurface of the metal therein, or there may be a suflicient space betweenthe plunger, the axis of which would be substantially vertical, and thecontainer to permit the former to act as a displacer causing the freesurface of the liquid metal in the container and mould to rise or fallaccording as the plunger, is moved. In another arrangement the level ofthe filling metal within the mould may be varied and controlled by meansof the admission plug or valve referred to and means provided forrunning out the filling metal. Provision must be made for maintainingthe whole of the metal to be introduced in a suitable liquid condition.In order to facilitate flow of the filling metal to all faces 'of theingot one or more distributing conduits may be provided. These would beformed preferably by removing or displacing parts of the mould wallcorresponding with the conduits, the said removal taking place after thecommencement of pouring of the steel and before the liquid filling metalis admitted to the mould.

The accompanyingdrawings illustrate somewhat diagrammatically and by wayof example various methods by which the invention maybe carried out inpractice.

Fig. 1 is an elevation, partly sectional, showing an ingot mould andmeans for delivering molten metal, such as lead, to the lower portion ofthe mould.

Figs. 2 and 3 are views similar to Fig. 1 showing.

other methods by which the melted lead may be caused to flow into thelower portion of the mould. Fig. 4 is a sectional view, drawn to anenlarged scale, of a valve, such as is indicated in Fig. 1, for

' wire 19 may be wound upon a metal drum 20, the

admitting the melted lead to the lower portion of the mould.

Fig. 5 is an elevation, the left-hand half being in section, showing ameans for cooling the outside of the mould at different levels.

Referring now to Fig. 1, a mould for casting steel ingots is indicatedin section at 1. The mould is illustrated as being about one-thirdfilled with the molten steel indicated at 2, the stream of metal to becast entering the mould being indicated at 3. -4 is a reservoircontaining lead which is maintained in a melted condition by means of afurnace in the space 5 below the said reservoir. The reservoir 4 issituated at a level above that to which it is desired the liquid leadshall rise in the ingot mould. The lower end of the reservoir.

4 communicates by a pipe 6 through a valve '7 with the lower portion ofthe mould as shown at 8.

' The valve '7 is operated through a shaft 9 rotated by means of a handwheel 10 from a platform 11. The outlet from the reservoir 4 to the pipe6 is regulated by a manually operable valve indicated at 12.

On the other side of the mould is shown a standpipe 13 whichcommunicates with the lower portion of the mould as shown at 14 througha valve 15,- which may be of a similar construction to the valve 7, saidvalve being operated by a shaft 16 and hand wheel 1'7.

18 is a device for indicating the level to which the metal rises in thestand-pipe l3 and thus the level to which the liquid lead has riseninthe space between the casting and the side of the mould. Such anindication may be given in various ways. For example, as shown, aflexible position of the lower end of the wire in the standpipe beingadjusted by rotating said drum. The wire and the metal in the stand-pipeare arranged to form part of an electric circuit including a suitablesource of electricity and an alarm or signal device, so that whenthemetal in the stand-pipe rises to such a height as to touch the end ofthe wire the circuit is completed and a signal is given. It is obviousthat many suitable devices can be employed, the one described beinggiven merely as an example.

To permit the flow of melted lead from the lower part of the mould, anoutlet 21 may be provided which is furnished with a shut-off cock of anysuitable description. The outlet delivers a flange 23 and is providedwith a branch 24 connected through a flange to the pipe 6 leading fromthe reservoir 4 and with an outlet 21. The barrel 22 t'erminates in anend piece 25' seated in an opening in the lower part of the mould andprovided with an orifice 26 by which the interior of the barrel cancommunicate with the interior of the mould. Said orifice is fitted witha plug 2'7 by which it can be opened and closed. At the outer end of thebarrel 22 is a'terminal gland 28 furnished with packing and which may beof any suitable construction.- The valve rod 29, which is adapted toslide in the gland 28, is connected to the plug 2'? by a socket 30 inwhich the inner reduced end of the plug 27 is secured by a pin 31. Theouter end of the valve rod 29 is reduced in diameter and is providedwith a screw thread 32 engaging with a nut 33 provided with bevel teeth34. The nut is rotatable on the screw thread 32 by means of a' bevelgear 35 mounted on the end of the valve operating spindle 9. The nut 33is maintained in position by means of a plate 36 supported from thebarrel 22 and a sleeve 3'7, one end of which engages with the nut 33 andthe other end of which engages with a bracket 38. The reduced portion ofthe valve rod 29 slides to and fro in an orifice in thebracket 38 and isprovided with a key or feather 39 which slides in a groove in saidorifice rotation of the valve rod when the nut 33 is rotated. It will beclear, without further description, that when the nut 33 is rotated inone or other direction by -means of the operating rod 9 and hand wheel10 the plug 27 will be moved in and out of the orifice 26. A gasket 40of asbestos or other suitable material adapted to stand the temperatureof the liquid lead may be provided between the socket 30 and the innerface of the end piece 25 of the valve barrel 22. The valve 15 (Figure1), by which the bottom of the mould is connected to the stand-pipe 13,may be of similar construction to the valve 7.

Referring again to Fig. 1, the ingot is illustrated as being aboutone-third poured, and its lower portion as having solidified, so that aspace 41 is formed between the lower portion of the ingot and the moulddueto the contraction of the ingot and/or the expansion of the, mould.During the initial stage of the pouring the valve '7 may be maintainedclosed so as to prevent the metal being poured from passing out of themould. .At a desired stage in the ipouringthe valve 7 is opened andliquid lead from the reservoir 4 is permitted to fiow into the pipe 6 byopening the valve 12 and thence into the space 41 between the lower partof the ingot and the mould. The level of the liquid in the space isregulated by operation of the valve12. In the drawings the level isshown by the line 42. The valve 15 is also opened, permitting the liquidmetal to fiow into the stand-pipe 13 by which its level inside the mouldis indicated as hereinbefore described. It will be understood thatduring the casting operation the pipe 6, the valve 7 and the stand-pipe13, with its valve 15 will be maintained at such a temperature as willpermit of the flow of the liquid lead from the reservoir 4 to the bottomof the mould, into the standpipe 13 or through the outlet 21 as desired.This may be done by external heating, for example by means of gas jetssuitably applied, not shown in the drawings.

The liquid filling metal may be admitted to the mould in this manner atany desired stage in the pouring, or even after the pouring is finished,in order to regulate the cooling and/or to supply a suitable hydrostaticpressure to the outside of the ingot as desired.

Notwithstanding that the lower part of the ingot or casting is restingon the base of the mould it is found that the liquid filling metal willpene-.

trate to the space between the ingot and the mould without difiiculty.In some cases means such as channels, not shown in the drawings, may beprovided for distributing the filling metal to the sides of the mould.

Referring now to Fig. 2, a. mould 1, of which the lower portion isprovided with valves such as valves '7 and 15 which may be similar tothe valves 7 and 15 hereinbefore described and illustrated in detail inFig. 4, but which are of somewhat different external appearance, isshown. The liquid low-melting metal is supplied to the lower portion ofthe mould from a reservoir 45 which is located below the valve '7 andconnected to said valve by a pipe 47. The liquid low-melting metal isforced by pressure of a suitable gas from the reservoir 45 into themould by way of the pipe 47 and valve '7 The gas, for example nitrogen,is supplied to the reservoir 45 from a gas bottle 43, connected to theupper end of the reservoir by a pipe 44 equipped with a regulating valve44 The low melting point metal, for example lead, may be maintained in amolten condition by a furnace, not shown, located in the space 46 belowthe reservoir 45. The reservoir 45 is provided with a pressure gauge 48.

The stand-pipe in this instance may be dispensed with and the height towhich the lead rises in the mould may be estimated from the pressureshown on the gauge 48. Instead of permitting the lead to escape througha pipe, such as the pipe 21, Figure 1, it may be permitted to run backinto the reservoir 45 by reducing the height and is provided with a ramor plunger 50 of somewhat smaller cross-sectional d mensions than thereservoir so that metal may rise freely in the space between the plungerand the walls .of the reservoir. It will be clear that, by raising andlowering the plunger 50 in the reservoir, the

low melting point metal may be forced through the pipe 47 into and outof the lower portion of the mould between the ingot and the mould asdesired. The level of the metal in the mould, as shown by the line 42,will obviously be the same as that in the reservoir 49. In this casealso the standpipe for indicating the level may also be dispensed with.

In Fig. 5 means are shown for cooling the mould externally. For thispurpose the mould 51, which may be of any desired form internally, isprovided on its exterior with ribs or fins 52 to facilita'e cooling. Amuif 53, made of sheet metal, has its upper and lower plates 54, 55shaped to cooperate with the ribs 52 and is adapted to be moved up anddown the mould as desired by means of chains or wire ropes 56. The muffis provided with an inlet 58 and an outlet 57-for the admission anddischarge of cooling air which is caused to flow, preferably in anupward direction, over the mould thereby causing a greater coolingeflect at that portion of the mould to which the muff is applied than atother portions. The cooling effect will also be greater at the lowerpart of the muif or where the cold air is admitted. In some cases theupper plate 54 of the muff may be omitted and the air therein maydischarge directly into the atmosphere. Arrangements such as shown inFig. 5 for cooling the mould at some parts more than at others may, ifdesired, be

employed in conjunction with arrangements for admitting liquid metal tothe lower part of the mould as previously described.

In some cases means may be employed for heating the upper end of theingot; for example the head part of the mould indicated at 59 in thedrawings may be lined with a refractory material of low thermalconductivity supplemented by heatingimeans. In one arrangement the headis made with double walls, the annular space I between the wallsconstituting a heating chamber which may conveniently be heated bygaseous or liquid fuel. In some cases, for example in the case of verylong ingots or castings, it may be desirable to apply heating means tothe upper part of the ingot as distinct from the head.

In some cases after the wall of the ingot or casting has been solidifiedto a sufiicient thickness it may be desirable to retard the rate ofcooling of the upper part of the ingot while in the lower portion therate of extraction of heat is intensified, for examp e by means such asabove described with reference to Fig. 5. In this case above a coolingjacket such as shown in Fig. 5

a heat insulating jacket or mufi may be employed which may be raisedwith the cooling mufi during the operation of freezing the ingot orcasting solid from the bottom upwards. Furthermore after the lower partof an ingot or casting has become solid it may be desired to retard thecooling to prevent the development of.

high internal stress. In this case heat insulating means or heatingmeans may be applied below the cooling jacket or muff.

Although I have herein described various methods of carrying out theinvention and illustrated various constructions in the drawings, it willbe understood that the invention is not limited to any particularconstruction of mould or accessary apparatus. Furthermoreit will beunderstood that the invention is not limited to the casting of ingots orpieces of simple shape, but may be'employed for the purpose ofincreasingthe soundness and quality of castings of other metals than steel and oflarger or more complex mitting the poured metal to partially solidify,

and introducing between at least a part of the solidified surface of themetal and the mold fluid metallic substance having a melting point lowerthan that of the metal being cast.

2. A process of producing metal castings, comprising pouring moltenmetal into a mold, and in introducing between at least a part of themetal and the mold, during the pouring operation and after partialsolidification of a poured portion of the metal, fluid metallicsubstance having a melt! ing point lower than that of the metal beingcast.

3. A process of producing metal castings, comprising pouring moltenmetal into a mold, and in introducing between at least a part of themetal and the mold, after the pouring operation and partialsolidification of the metal, fluid metallic substance, having a meltingpoint lower than that of the metal being cast.

4. A process of producing metal castings, comprising pouring moltenmetal into a mold, permitting the poured metal to partially solidify,in-

troducing between at least a part of the solidified surface of the metaland the mold fluid metallic substance having a melting point lower thanthat of the metal being cast, and. varying the level of the metallicsubstance in the mold.

5. A process of producing metal castings, comprising pouring moltenmetal into a mold, permitting the poured metal to partially solidify andintroducing molten lead between the mold and at least a part of thesolidified surface of the metal being cast.

6. A process of producing metal castings, comprising pouring moltenmetal into a mold, permitting the poured metal to partially solidifiy,introducing between at least a part of the solidified surface of themetal and mold fluid metallic substance having a melting point lowerthan that

